Field
The present invention relates to an infrared spectrum analysis technology and device for gas, more particularly, relates to an infrared detection device for coal mine polar gas and a detection method for the same.
Description of Related Art
Different oxidation stages of spontaneous combustion of coal correspond to different auto-ignition temperature ranges, different kinds and concentrations of gas products. The gas products for forecasting and predicting the spontaneous combustion process typically include CO, CO2, CH4, C2H6, C3H8, C4H10, C2H4, C3H6, C2H2, and the like. The spontaneous combustion of coal can be precisely forecasted according to constitution, concentration, changing rate and other characteristics of the oxidized gas products, which can allow a coal mine to be fire-proofed for safe production of work. The indications for detecting spontaneous combustion mainly include the indication of CO and derivative thereof, the indication of alkene-alkane ratio, the indication of alkyne gas, the indication of alkane ratio and the like.
During the management and reuse of a mine closed for a fire, the composition of the gas in the fire site should be monitored. At this time the monitored gases mainly comprise CO, C2H2, C2H4. However, after a gas explosion at a coal mine, the main noxious gases comprise CO, C2H4, C2H6 and the like. Thus, during the production of coal, in order to prevent the spontaneous combustion of coal and the gas explosion of the coal mine whether in the daily production of coal or in the emergency and rescue after the disaster, the above-mentioned gas should be analyzed quickly and precisely.
Current gas detection methods for the coal mine industry comprise a sensor-based method and a gas chromatography. The sensor-based method is impacted by downhole conditions and the detection result thereof thus has relatively large error. For instance, in case of low concentration of oxygen, a methane sensor equipped in a present portal explosion measuring instrument will produce a result with relatively large deviation. As for the gas chromatography, different components of the gas to be detected have to be adsorbed to and desorbed from a chromatographic column at different time periods, thus the whole analysis may take a long time such that a timely analysis cannot be achieved. Meanwhile the chromatographic column in the chromatographic analysis device may require frequent maintenance. Furthermore, the procedure of the chromatographic analysis system generally has to test a sample first each time, thus the technology is quite complicated and the analysis result will vary from person to person due to the different levels of technical skill.
An infrared spectrum analyzer may analyze the gas with the help of a gas pool. Since impacted by the structure of the gas pool, background gas inside the pool cannot be completely discharged, which may have a adverse impact on the test result. When gas concentration is monitored by being sampled continuously, this impact will be moderated by blowing gas over a longer period of time. However, the interference gas eventually cannot be thoroughly discharged. With regard to the investigation of fire accidents at coal mines, the gas to be analyzed is gathered by a person downhole of the coal mine. However, the interference of background gas inside the pool may only be eliminated by the person through gas blowing. As well, the gas inside the gas pool may be very hard to be substituted by the gas to be analyzed, which may produce a great impact on the accuracy of the gas quantificational analysis result of the infrared spectrum method.
Recently, as for the infrared detection device for coal mine polar gas and a detection method for the same, the detection device may comprise Bruker Tensor 27, Bruker ALPHA made in Germany, and Perkin Elmer Spectrum 100 made in the USA. The above-mentioned devices may both comprise a central processor, which can be electrically connected to a power supply, a light source, a detector, an alarm and indication lamp, an input and output module, a data collection and storage module. The power supply may also be electrically connected to a power supply switch and a power supply interface. The input and output module may also be connected to a computer communication interface. The data collection and storage module may also be electrically connected to the detector. As well, a detachable gas pool with a gas inlet and a gas outlet may be provided between the light source and the detector. The method for this infrared detection device for coal mine polar gas with such structure may comprise the following steps: firstly detaching the gas pool during the gas detection and filling N2 gas of 99.999% content into the gas pool from the gas inlet; after replacing the gas in the gas pool, closing the gas outlet firstly and closing the gas inlet until the pressure is balanced; putting back the gas pool; scanning the spectrogram of the background gas until there is no gas peak value; during the hand sampling, connecting the gas bag filled with the gas to be detected to the gas inlet, opening the gas inlet valve and then opening the gas outlet valve; pressing the gas to be detected into the gas pool until the N2 is completely discharged, closing the gas outlet valve and then the gas inlet valve; scanning the spectrogram of the gas to be detected so as to analyze the gas to be detected. Since there are blind angles at both ends inside the gas pool, the background air cannot be thoroughly replaced by N2 and then N2 cannot be thoroughly discharged, which render the spectrum of the gas to be detected distorted and the analysis of the gas to be detected inaccurate, thus, there are some risks of causing safety misadventure at the coal mine. Furthermore, in the method for this infrared detection device for coal mine polar gas with such structure, the gas pool has to be detached and is complicated to be used. Thus, there is a need for devices and methods to analyze the above-mentioned gases in an effort to ensure continuous production within a mine and safety of mine workers.